By Addison Speck, Reporter

EVANSDALE, Iowa - Tuesday marks four months since the disappearance of 9-year-old Elizabeth Collins and her 11-year-old cousin, Lyric Cook-Morrissey.

Authorities believe the girls were abducted from Evansdale on July 13, while they were on a bike ride. Hundreds of volunteers searched for the girls, authorities also drained Meyers Lake during the search.

The parents of two girls abducted wrote an open letter to the girls' kidnapper. The letter was posted on the The Waterloo-Cedar Falls Courier website Tuesday morning.

The letter was posted online at about 9 a.m. is titled "To Whom It May Concern."

It starts by saying the families have no idea who the kidnapper is, but they know something about the person. "Because only someone who hurts inside would hurt another person and their family," reads the letter.

The letter talks about the pain that the families have experienced. It calls on the person to be "a hero, not a monster." The letter asks the person to let the girls come home. It is signed by Drew and Heather Collins and Dan and Misty Morrissey-Cook. "You don't need to do it in a public place where there are video cameras and you are worried about that. A park is fine, there is always houses near by they can go to a house," said Heather Collins.Click here to view the letter.

Their plea in the paper was followed by the Collins and others passing out fliers across the state. Collins said they passed out some at Iowa truck stops but others were even distributing them in Colorado and Omaha.

Collins said she still finds people out there who don't know anything about the case. That's why family, friends, and members of the community at Tuesday nights prayer vigil were also given fliers before they walked out the door. "The more people that see the fliers the better. Obviously, there hasn't been too many new breaks in the case that we know of, so as many people that see them, that's what we are trying to do here. Just keep raising awareness, keep putting it out there," said Sarah Curl, of Waterloo.

The vigil was at the Courtside Vineyard Church in Evansdale. "one of the things we just pray is that the people who haven't heard will hear and maybe the right person will hear that has seen them," said Joe Fagar, the Associate Pastor at the church.

In the letter the families beg the girls abductor not to wait and just let them go. "We forgive them. God forgives them. We just want them back, we don't need to know anything else," said Heather Collins.

The Black Hawk County Sheriff's Department issued a statement Tuesday afternoon: "While law enforcement has nothing new to report on the girls we continue to receive good tips regarding their disappearance and those tips are being followed up on.

We wish to reiterate that anyone that has information concerning this case or was in Evansdale on July 13th between 12:00 p.m. and 6:00 p.m. that may have seen the girls riding their bicycles or in the area of Meyers Lake that have not talked to law enforcement to call in on the tip line at 319-232-6682 or 1-800-346-5507."